The problem with the powerwall is the 500 cycle limit. The market where power outages are frequent but lots of people are affluent is very limited. For the same money, you could get a very smart Sonnen energy center from Germany with 10 000 recharge cycles and do your own micro-grid with solar panels and neighbors.
We tried the Tesla-related Solar City for our residence -- they sent out a gum-chewing salesman whereas a locally based solar panel company sent out a licensed contractor with a college degree in electrical engineering. We climbed up on the garage roof, measured with a tape measure, and 10 minutes later had maxxed out a design which gets us totally off coal and nuclear with 21 x 315 watt LG panels. (We use 15 000 kwh per year, 900-1800 monthly extremes.) There was surprisingly little to be gained from optimally orienting the panels. The ROI was still a respectable 10 years though not a big factor in deciding to go forward.
We went with micro-inverters, one per panel to get AC on a parallel circuit, rather than a high DC current to a single expensive point of failure. LG makes a 360 watt panel of the same dimensions but there is no proven micro-inverter for it yet.
The system was very affordable and includes a free monitoring device for each circuit in our electrical panel. This goes online through our existing household router. [[Please do not hack the refrigerator, we like the beer cold over here.]]
We learned that our 1.5 horsepower pump on the pool filter makes up a preposterous proportion of our yearly electric use, an 1100 watt light bulb running 8 hours a day. It came with the house, along with a gigantic propane tank to heat the water, but sees only occasional use. It could be made a wildlife pond but we already have 4 of those. The pool pump was not the only low-hanging fruit on the energy audit, the living room door had a terrible seal etc.
A solar system is all plug-and-play today, no more difficult than plugging a mouse cord into the back of a computer. I could have ordered a shipping container of panels online and done the installation cheaper myself. However there are issues with the numerous permits required and whether the homeowner has the necessary qualifications (eg roof is not supposed to leak after installing mounts, panels should not blow off in high winds).
Our local utility fears distributed solar will disrupt its lazy business model and works tirelessly at rate hearings to bring on punitive retroactive tariffs. Mind you, this is a member-owned electric cooperative, not a for-profit entity though I can't recall our input ever being solicited.
I had not appreciated the significance of summer vs winter vs year-average power consumption. To completely get rid of the utility means installing too many panels, enough to meet peak use will sit idle most of the year however much battery storage. However we can go with more panels, Sonnen batteries and consumption reduction if the utility clings to its antisocial path.
The utility sent us a 28-page form of terms and conditions that our installation has to satisfy. Some of it makes sense, to keep people from loading all sorts of rubbish on the power lines that will degrade the system with fluctuations in voltages and hertz that annoy or even bring down the neighbors. There are also serious safety issues involving first responders to house fires, malfunctioning equipment over the years, and auto-disconnects from lightning strikes.
Our solar company installs one system after another, 2-3 a week, year after year, so they don't put up with nonsense from the utilities and inspectors. We would have done this years ago had we known about them. Doing a web search had proven a real time-waster, so many rip-offs and charlatans that are a gamble for a 25-year system; we only learned about our company from another homeowner during a garden tour.
